Preparation of polymers

ABSTRACT

Production of polymers of conjugated dienes and/or vinylsubstituted aromatic compounds utilizing, in said production, polymerization initiator compositions comprising reaction products of C2-C12 alkyllithiums with monomers from the group of polymerizable conjugated dienes and polymerizable vinylsubstituted aromatic compounds in a medium of aliphatic, cycloaliphatic or aromatic hydrocarbons and/or aliphatic tertiary monoamines or aryl ethers, the conjugated diene and vinylsubstituted aromatic compound portion of said initiator compositions being relatively nonpolymeric.

Morrison et a1.

[ 1 Apr. 3, 1973 1541 PREPARATION OF POLYMERS [75] inventors: Robert C.Morrison; Conrad W.

Kamienski, both of Gastonia, NC.

[73] Assignce: Lithium Corporation of America, v

New York, NY.

[22] Filed: Aug. 25, 1971 [21] Appl. No.: 174,919

Related U.S. Application Data [62] Division of Ser. No. 4,126, Jan.,1970, Pat. No.

[52] U.S. Cl. ..260/84.7, 252/431 R, 260/47 UA, 260/82.1, 260/83.1,260/83.5, 260/88.3 A,

260/94.2 M, 260/665 R, 260/879, 260/880 B [51] Int. Cl. ..C08f 3/16,C08f 7/04, C08f 19/04 [58] Field of Search ..260/93.5 S, 94.2 M, 84.7

[56] References Cited UNITED STATES PATENTS 3,294,774 12/1966 Gerber etal. ..260/94.2 M

3,301,840 1/1967 Zelinski ..260/94.2 M 3,317,918 5/1967 Foster 3,388,1786/1968 Kamienski et al ..260/94.2 M

Primary ExaminerHarry Wong, Jr. Attorneywallens'tein, Spangenberg,Hattis Strampel [57] ABSTRACT Production of polymers of conjugateddienes and/or vinyl-substituted aromatic compounds utilizing, in saidproduction, polymerization initiator compositions comprising reactionproducts of 0 -0,, alkyllithiums with monomers from the group ofpolymerizable conjugated dienes and polymerizable vinyl-substitutedaromatic compounds in a medium of aliphatic, cycloaliphatic or aromatichydrocarbons and/or aliphatic tertiary monoamines or aryl others, theconjugated diene and vinyl-substituted aromatic compound portion of saidinitiator compositions being relatively nonpolymeric.

8 Claims, No Drawings PREPARATION OF POLYMERS This is a division ofapplication Ser. No. 4,126, filed Jan. 1970, and now U.S. Pat. No.3,668,263.

This invention relates to the production of polymers of conjugateddienes and/or vinyl-substituted aromatic compounds using certaininitiators which are derived from C -C alkyllithiums and polymerizableconjugated dienes and/or polymerizable vinyl-substituted aromaticcompounds, especially polymerizable vinylsubstituted aromatic compoundswhich are reacted in a manner described hereafter in detail in a mediumof aliphatic, cycloaliphatic or aromatic hydrocarbons and/or aliphatictertiary monoamines or aryl ethers.

It has heretofore been known, as shown in U.S. Pat. No. 3,377,404, toprepare alkyllithium initiators, for use in the polymerization ofconjugated dienes and vinyl-substituted aromatic compounds, by aprocedure comprising initially preparing an organo polylithiumpolymerization initiator in a polar solvent, such as diethyl ether, thensolubilizing said initiator by reacting the same with a small amount ofa conjugated diene, then replacing a substantial portion of the polarsolvent with a hydrocarbon diluent, and thereafter contacting thesolubilized organo polylithium initiator with a conjugated diene in thehydrocarbon diluent substantially reduced in polar solvent content toeffect polymerization of said conjugated diene. The objective is to makeconjugated diene polymers or copolymers of conjugated dienes withvinyl-substituted aromatic compounds with low viscosities and withnarrow molecular weight distribution. A particular advantage of usingsaid known initiators is that the usual initiation step inpolymerization is avoided, propagation proceeding directly to producelargely monodisperse polymers. These initiators, in the form of adducts,can be prepared in a hydrocarbon medium in the presence or absence ofaliphatic or cycloaliphatic ethers. In the absence of ethers, theadducts, as heretofore prepared, possess a relatively high molecularweight and are soluble in the medium only in relatively lowconcentration. On the other hand, when prepared in the presence of saidethers, the adducts, when used as catalysts for the polymerization ofl,3-conjugated dienes, do not produce the desired high l,4-polymermicrostructure. Thus, addition of alkyllithium compounds to, forexample, doubly-substituted vinyl-aromatic compounds, as heretoforecarried out, produces only higher molecular weight polymers ornecessitates the presence of undesirable ethers to produce adducts ofreasonably low molecular weight and high solubility.

Our present invention is sharply distinguished from that of said U.S.Pat. No. 3,377,404, in that, among other things, it is whollyunnecessary, in the preparation of the initiators utilized in accordancewith our invention, and, indeed, is most desirably expressly avoided,initially to form an organo polylithium polymerization initiator in apolar solvent followed by the procedures referred to above in saidpatent. In addition, as will be shown in detail below, the initiatorcompositions used in accordance with the present invention distinguishin structure and properties from those of the aforesaid patent.

An object is to provide an improved process for preparing conjugateddiene and vinyl-substituted aromatic polymers and copolymers.

Further objects, advantages and features of our invention will beapparent from the following disclosures.

The polymerization initiator compositions or adducts, of extremely lowmolecular weight used, in accordance with our invention, forpolymerizing conjugated dienes and/or vinyl-substituted aromaticcompounds to polymers of relatively low vinyl content, can be preparedby the gradual and controlled admixture of a polymerizable conjugateddiene monomer or of a vinyl-substituted aromatic compound with analkyllithium compound, in a medium as described in detail below, and,more particularly, by the gradual and controlled addition of saidpolymerizable monomer to a liquid hydrocarbon medium containing analkyllithium and varying amounts of an aliphatic tertiary monoamineand/or aryl ether activator. In fact, the solvent medium may be puresolely aliphatic tertiary monoamine or solely aryl ether, although thisis generally not preferable. We have further found that not only is thereaction rate increased in the formation of the adduct, but it ispossible to obtain adducts of exceptionally high molarity, based on thelithium, this latter effect being realized by keeping polymerization ofthe diene and/or vinyl-substituted aromatic compound at a low value or apractical minimum. Thus, in the initiators of our invention, themonomeric character of the monomer portion thereof is most desirouslyobtained although dimerization of the monomer may be present to agreater or lesser extent. Essentially all of the alkyllithium employedshould be used up in the production of the initiator so that there is noor essentially no free alkyllithium present. Polymerization proper ofthe monomer is to be avoided in the production of the initiator and, inthis connection, it may be noted that dimerization is not considered tobe included within the meaning of the term polymerization."

The reaction temperatures at which the initiators are produced arevariable but, generally speaking, low temperatures are used, usually inthe range of about C to not substantially in excess of ambienttemperatures, particularly desirably being temperatures in the range ofabout 0 to 30 C.

The initiators or adducts used in accordance with the present inventionare characterized by substantial uniformity. Thus, in the case of single(or mono-) addition of alkyllithiums to each vinyl substituent onbenzene, adducts have little or no concomitant oligomerization orpolymerization of the vinylbenzene. Vinylbenzenes such as styrene andmeta-divinylbenzene have a high propensity toward polymerization in thepresence of alkyllithium catalysts. Adducts used in accordance with ourinvention can be prepared quite economically, utilizing a minimum ofconjugated diene monomer or vinyl-substituted aromatic compound monomer,and, in use for polymerizing such monomers, they contribute little orinsignificantly to the polymers resulting from their use as initiatorsor catalysts. Moreover, as will be shown below, difunctional orpolyfunctional initiators or catalysts can be prepared as readily asthose of monofunctional character. Such difunctional initiators orcatalysts can be used to produce self-vulcanized" tri-block polymers ofpredetermined molecular weight which are useful in producing variouselastomeric rubbery products by molding and extrusion techniques.

The amount of the hydrocarbon reaction medium which is employed incarrying out the production of the initiator is variable but, generallyspeaking, it will usually fall within the range of about to [00 moles ofthe hydrocarbon to l of the alkyllithium.

The amount of tertiary monoamine and/or aryl ether employed in thepreparation of the alkyllithium adducts is variable and will usuallyfall within the range of about 0.01 to l0 equivalents per equivalent ofalkyllihium utilized, and preferably from 0.2 to 2 equivalents perequivalent of alkyllithium when the solvent medium is a liquidhydrocarbon.

Polymerizable conjugated dienes employed in the production of theinitiators or adducts are l,3-conjugated dienes containing from four tol2, inclusive, carbon atoms per molecule. Examples thereof include thefollowing: l,3-butadiene; isoprene; 2,3-dimethyl-l,3- butadiene;1,3-pentadiene (piperylene); 2-methyl-3- ethyl-1,3-butadiene; 3-methyl-l,3-pentadiene; l,3-hexadiene; 2-methyl-l,3-hexadiene; and 3-butyl-l,3-octadiene. Among the dialkylbutadienes, it is preferred that thealkyl groups contain from one to three carbon atoms. Numerous others aredisclosed, for instance, in U.S. Pat. No. 3,377,404, the disclosure withrespect to which is incorporated herein by reference.

In addition to or in place of the above described conjugated dienes,polymerizable vinyl-substituted aromatic compounds can be combined withalkyllithium compounds to form polymerization initiators or adducts.These compounds include styrene; alphamethylstyrene; l-vinylnaphthalene;2-vinylnaphthalene; l-alpha-methylvinylnaphthalene; 2-alpha-methylvinylnaphthalene; 1,2-diphenyl-4-methylhexene-l;l,6-diphenyl-hexadiene-l ,5; l,3-divinylbenzene; 1,3,5-trivinylbenzene;l,3,5,-triisopropenylbenzene; l,4-divinylbenzene; l,3-distyrylbenzene;1,4- distyrylbenzene; 1,2-distyrylbenzene; and mixtures of these, aswell as alkyl, cycloalkyl, aryl alkaryl and aralkyl derivatives thereofin which the total number of carbon atoms in the combined hydrocarbonconstituents is generally not greater than 12. Examples of these lattercompounds include: 3-methylstyrene; 3,5- diethylstyrene;2-ethyl-4-benzylstyrene; 4-phenylstyrene; 4-p-tolylstyrene;2,4-divinyltoluene; 4,5- dimethyl-l -vinylnaphthalene;2,4,6-trivinyltoluene; and 2,4,6-triisopropenyl-toluene. Again,reference is made to U.S. Pat. No. 3,377,404 for disclosures ofadditional vinyl-substituted aromatic compounds which are incorporatedherein by reference.

Especially satisfactory for the production of the initiators aremeta-divinylbenzene and styrene.

In describing our invention, the polymerizable conjugated dienes andvinyl-substituted aromatic compounds are generically, and forsimplicity, sometimes referred to as monomers.

The alkyllithiums which are adducted with the monomers to produceinitiators or adducts used in accordance with the present invention aregenerally in the C -C range and include, for example, ethyllithium,n-propyllithium, isopropyllithium, n-butyllithium, isobutyllithium,sec-butyllithium, tert-butyllithium, namyllithium, isoamyllithium,sec-amyllithium, and tertamyllithium. Of especial utility are secondaryand tertiary alkyllithiums such as isopropyl lithium, sec-butyllithium,tert-butyllithium. While, in the broader aspects of the presentinvention, the mole ratio of monomer to alkyllithium used in theproduction of the initiators or adducts may be varied from I to of themonomer to l of the alkyllithium, and preferably from 1 to 10 of themonomer to l of the alkyllithium, a particularly important mole ratiorange being from 1 to 2 of the monomer to l of the alkyllithium.

The aliphatic tertiary monoamine activators are generally low molecularweight trialkylamines possessing no methyl groups, and they include, byway of example, triethylamine, tri-n-propylamine, triisopropylamine,ethyldi-n-propylamine, diethyl-n-butylamine, and triisobutylamine.Arylalkyl tertiary monoamines may also be used, illustrative of whichare dimethylaniline, diethylaniline, diisopropylaniline, andmethylisobutylaniline. Aryl others which function as activators which donot produce a high vinyl microstructure in polydienes produced with theadducts may also be used in place of or in conjunction with thealiphatic tertiary monoamines. These are alkylarylethers such asanisole, ethylphenylether, isopropyl phenylether, dibenzylether andn-butylphenylether and diarylethers, such as diphenyl ether, di-p-tolylether, and phenyl-o-tolyl ether. Especially satisfactory aretriethylamine, dimethylaniline and anisole.

The hydrocarbon solvent media which may be, and, generally,advantageously are employed are normally liquid alkanes and cycloalkanessuch as n-pentane, nhexane, n-heptane and cyclohexane, and normallyliquid aromatic hydrocarbons, such as benzene, toluene, xylene,ethylbenzene and pseudocumene, as well as various mixtures of thesetypes. The concentration range of the adducts in solution may be variedwidely, with solutions containing between about 0.5 and 2 equivalents ofadduct, based on lithium, being particularly desirable.

The addition of alkyllithiums to the monomer or monomers can becontrolled to give exclusively 1:1 adducts based on the alkyllithium andactivated vinyl groups present. Thus, for example, addition of styreneto a solution of sec-butyllithium in hexane containing an equivalent oftriethylamine at 0 C results in the formation of approximately 97 molepercent of l-Lithio- 3-Methylpentylbenzene:

CHCH1CH CHzC a The foregoing (I) and (II) adducts possess a highsolubility in hydrocarbon solvents. The (II) adduct is difunctional andhas marked utility in preparing triblock rubbery polymers.

The monoand difunctional adducts of alkyllithiums and monomers in whichthe adduct is the result of the addition of one alkyl group originallypresent in the alkyllithium per activated vinyl group originally presentin the monomer, and particularly the difunctional adducts are especiallyvaluable initiators. Illustrative examples of such adducts, in additionto those mentioned above, are 1-lithio-5methylheptene-Z; 3-lithiomethyl-4-methylhexene-l; l-lithio-3,5-dimethylheptene-2; 3-lithiomethyl-Z,4-dimethylhexene-1; trisl ,3 ,5-( 1-lithiol,3dimethylpentyl)-benzene; and 1,4-bis-(l-lithio-3-methylpentyl)-benzene.

The monomers which can be polymerized in the presence of thealkyllithium adducts employed in the practice of our invention arepolymerizable conjugated dienes containing from four to 12 carbon atoms,preferably four to eight carbon atoms per molecule, and polymerizablevinyl-substituted aromatic compounds. Examples of these conjugateddienes are the same as those given in regard to the monomers used in theinitiator preparation. In addition, the above conjugated dienescontaining substituents along the chain can also be employed, such as,for example, halogenated and alkoxy-substituted conjugated dienes suchas chloroprene; fluoroprene; 2-methoxy-l,3-butadiene;2-ethoxy-3-ethyl-l,3-butadiene, and the like. Of the conjugated dienes,the particularly preferred monomers are l,3-butadiene, with isoprene andpiperylene also being especially suitable. The conjugated dienes can bepolymerized alone or in admixture with each other to form copolymers orby charging the dienes sequentially to form block copolymers. Thevinyl-substituted aromatic compounds, which may be polymerized as such,or which can be copolymerized with the dienes, include those mentionedabove, such as styrene, l-vinylnapthalene, 2-vinylnaphthalene, as wellas the alkyl, cyclo-alkyl, aryl, alkaryl, aralkyl, alkoxy, aryloxy, anddialkylamino derivatives thereof in which the total number of carbonatoms in the combined substituents is generally not greater than 12,examples of such derivatives being 3-vinyltoluene; 4- phenylstyrene;4-cyclo-hexylstyrene; 4-p-tolylstyrene; 3,5-diphenylstyrene;4-methoxystyrene; 4- dimethylamino-styrene; 3,5-diethylaminostyrene; 3-ethyl-l -vinylnaphthalene; 6-cyclohexyl- 1 -vinylnaphthalene;6-benzyl-2-vinylnaphthalene; 4-methoxyl-vinylnaphthalene; 6-phenoxyl-vinylnaphthalene, and the like. The vinyl-substituted aromaticcompounds can be copolymerized with the conjugated dienes to form randomor block copolymers. Generally, the presence of trialkyl monoamines ordialkylanilines, or diarylethers and alkylarylethers preferably inlimited amounts, does not adversely affect the microstructure of theresulting polydiene polymers, which is in marked contrast to the adverseeffects of the presence of simple alkyl or cycloalkyl ethers such asdiethyl ether or methyl cyclohexyl ether.

In one aspect of the practice of our invention, polar monomers can beemployed to form block copolymers with the conjugated dienes. The polarmonomer is charged after the conjugated diene has polymerized.

Among the polar monomers applicable are for instance, vinylpyridines andvinylquinolines in which the vinyl group is positioned on a ring carbonother than a beta carbon with respect to the nitrogen. These pyridine,quinoline and isoquinoline derivatives can carry substituents such asalkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkoxy, aryloxy anddialkylamino groups, the total number of carbon atoms in the combinedsubstituents being generally not greater than 12. Also, there should beno primary or secondary alkyl groups on ring carbons in the alpha andgamma positions with respect to the nitrogen. Examples of theseheterocyclic-nitrogen polar monomers are 2-vinylpyridine; 4-vinylpyridine; 3,5diethyl-4-vinylpyridine; S-cyclohexyl-2-vinylpyridine;3benzyl-4-vinylpyridine; 6-methoxy-2-vinylpyridine;3,5dimethyl-4-dimethyl-amino-Z- vinylpyridine; 2-vinylquinoline;l-vinylisoquinoline; 3- methyl-4-ethoxy-2-vinylquinoline;3-dimethylamine-3- vinylisoquinoline, and the like. Still other polarmonomers which can be utilized include acrylic and alkacrylic acidesters, nitriles, and N,N-disubstituted amides, such as methyl acrylate,methyl methacrylate, butyl methacrylate, acrylonitrile,methacrylonitrile, N,N-dimethylacrylamide, N,Ndiethylmethacrylamide,vinylfuran and N-vinylcarbazole.

Our invention makes possible, readily and simply, the production ofpolymers and copolymers, for instance, l,3-butadiene polymers andcopolymers of 1,3- butadiene and styrene, said polymers possessing ahigh proportion of 1,4 links, and the central polybutadiene blocks ofsaid copolymers possessing a high proportion of 1,4 links, notsubstantially less than percent and,

, better still and commonly, percent and higher.

Illustrative, non-limiting examples of the practice of our invention areset out below. Numerous other examples can readily be evolved in thelight of the guiding principles and teachings contained herein. Alltemperatures recited are in degrees Centigrade.

EXAMPLE I Preparation of l,3-Bis-( l -lithio-3-methylphenyl)- benzene 60ml of a 1.82N sec-butyllithium solution in hexane (0.109 moles) and 6.8ml (4.9 g-0.049 moles) of triethylamine were charged to a dry,argon-flushed, 250 ml 3-necked reaction flask. The reaction flask wasequipped with stirrer, thermometer, addition funnel and a dry ice-hexanecooling bath. The flask and contents were cooled to 20 andmeta-divinylbenzene (M-DVB) (6.3 g 0.049 moles) diluted with 50 mlhexane was added dropwise over a period of 30 minutes. The reactiontemperature was held between 20 and 25 throughout the M-DVB addition andfor 2 hours longer. Gas-liquid chromatographic analysis of an active anda hydrolyzed sample of the reaction mixture revealed virtually nosec-butyllithium or M-DVB and the presence of one major and one minorproduct. A volume of 112 ml of a clear, deep' red solution was found tobe 0.96 N, while the active carbon-lithium content was 0.95 N (99percent carbon-lithium active product). 45 ml of the product washydrolyzed with dilute aqueous HCl. The organic layer was collected,dried and distilled using a vacuum micro-distillation apparatus.Gas-liquid chromatographic analysis of the organic layer prior tofractionation showed the presence of two components (designated A and B)in a weight ratio of 88 to 12. Two fractions were obtained after solventremoval and fractionation under reduced pressure. The first fraction,containing 95 percent of component A and percent of component B, boiledat 290 (corrected to 760 mm), and possessed a molecular weight (VPO) of257. The second fraction, containing 86 percent of component B and 14percent of component A, boiled at 540 (corrected to 760 mm) andpossessed a molecular weight (VPO) of 385. Since the first fraction wascontaminated with 5 percent of component B, the molecular weight ofcomponent A was corrected to 252 by utilizing the known molecular weightof fraction B. The theoretical molecular weight forl,3-bis-(3-methylpentyl)benzene is 246. The NMR spectrum of the firstfraction exhibits a singlet at 6.958 (4Hpheny1), a triplet at 2.558 (J=7cps) (41-1s benzylic methylene), a multiplet between 1.1 and 1.75centered at 1.48 (8H aliphatic methylene 2H methine) and an overlappingdoublet and triplet centered at 0.95 and 0.908 (12H methyl). The above,

NMR spectrum confirms the identity of component A to be1,3-bis-(3-methy1penty1) benzene. Component B was tentatively identifiedas 3-methyl-5,7-di-[m-(3- methylpentyl)-phenyl] heptane, the hydrocarbonanalogous to the product of the addition of the dilithio analog ofcomponent A to m-vinyl-(l-lithio-3-methylpentyl)-benzene.

Carbonation of 50 ml of the product solution yielded 8.3 g of an acidsalt [theory for free acid (see below)= 8.3 g]. A neutralizationequivalent (N.E.) of 163 was obtained on the free acid. The theoreticalN.E. for 1,3- bis-(1-carboxy-3-methylpentyl) benzene is 167. 90millequivalents of the product were reacted with 180 moles oftrimethylchlorosilane. The trimethylsilyl derivatives were isolated byhigh vacuum microdistillation. Fraction 1 boiled at 335, while fraction2 boiled above 500 (both b.p.s corrected to 760 mm). Carbon, hydrogenand silicon analyses on fraction 1 showed the presence of twotrimethylsilyl groups in the product and the product to be1,3-bis-(1-trimethy1sily1-3- methyl-pentyl)-benzene. Calcd: Si 14.37percent, C 73.76 percent, H 11.87 percent. Found: Si 14.01 percent, C73.38 percent, H 12.05 percent.

NMR analysis of the first fraction exhibits a multiplet at 7.1 (4aromatic Hs), a triplet centered at 2.18 (2 amethine l-ls), a singlet at0.98 (12-methyl hydrogens), a singlet at 0.058 (18 trimethylsilyl H's)and a broad multiplet centered at 1.48 (8 methylene Hs and 2 methinel-ls). The above NMR spectrum confirms the identity of fraction 1 to be1,3-bis-(l-trimethylsilyl-3- methyl-pentyl) benzene. These derivativescorroborate the identity of the adduct as being 1,3-bis-(1-lithio-3-methylpentyl) benzene.

EXAMPLE 2 Preparation of l-Lithio-3-methylpentylbenzene 110 ml of 1.82 Nsec-butyllithium in hexane (0.2 moles), 30 ml (0.22 moles) oftriethylamine, and 50 ml of n-hexane were charged to a 500 ml, S-neckedreaction flask equipped as above. The flask and contents were cooled to0 and 21 ml of styrene (0.2 moles), diluted with 50 ml of hexane, wasadded slowly over a period of 1 hour. The reaction temperature was heldat 0 throughout the styrene addition and for 1 more hour afterwards. Anintense, Carmine-red solution was obtained as the final product whichwas identified as 1- Lithio-3-Methylpentylbenzene. Gas-liquidchromatographic analysis of the hydrolysis products of the reactionmixture revealed the absence of sec-butyllithium and the presence of onemajor and one minor new component. The major new component, constituting97 mole percent of the product mixture, was found after fractionaldistillation to be 3-methylpentylbenzene, b.p. -205. Its NMR spectrumexhibited absorptions at 7.128 (singlet 5 phenyl hydrogens), 2.528(triplet-2 benzylic hydrogens J 7.5 1112.), 1.05-1.708 (multiplet 4methylene hydrogens and one methine hydrogen), and 0.908 (broadabsorption 6 methyl hydrogens).

EXAMPLE 3 The conditions of Example 1 were varied with regard to thetemperature during reaction, which was raised to 0 from -20, and to theratio of sec-butyllithium to M- DVB which was lowered from 1.1 toexactly 1.0. A 0.912 N solution (active and total base) was obtained.The mole percent of the lithium analog of component A[1,3-Bis-(3-Methylpentyl) benzene] was found to have decreased from 97to 67, while the trilithio analog of component B was found to haveincreased from 3 mole percent to 33 mole percent.

EXAMPLE 4 Example 2 was repeated using 0.037 moles of sec-butyllithium(in hexane), 0.040 moles of triethylamine, and 0.20 moles of styrene. Adark red, viscous 0.3 N solution was obtained, containing no unreactedsec-butyllithium, and an oligomeric soluble polystyryllithium withaDPof5.5.

EXAMPLE 5 Example 2 was repeated using 0.066 moles of secbutyl-lithiumin hexane, 0.10 moles of triethylamine, and 0.37 moles of 1,3-butadiene.A deep orange, fluid, 0.68 N solution was obtained, containing nounreacted sec-butyllithiurn, and an oligomeric solublepolybutadienyllithium with a I? of 5.6.

EXAMPLE 6 To a stirred slurry of 5 g of 1,4-distyrylbenzene(0.0177mo1es) in 30 ml of benzene there was added, during a period of 15minutes at room temperature, 28.7 ml of a 1.24 N solution ofsecbutyllithium in hexane (0.0355 moles) and 4.6 ml (0.034 moles) ofN,N- dirnethylaniline. The solution turned a deep red, but little heatwas evolved. The solution was checked periodically for unreactedsec-butyllithium. After 18 hours, 93 percent of the sec-butyllithium hadreacted yielding a dark red solution containing 0.33 equivalents perliter of carbon-lithium active product. The dicarboxylic acid obtainedon carbonation of this solution in dry iceether was analyzed by NMR. TheNMR spectrum of the diacid in CDCl;, exhibited absorptions as follows:Broad absorption between 6.5-7.88-14 phenyl hydrogens, multipletcentered at 4.148-2 methine hydrogens on carbons bearing the 2 COOHgroups, doublet of doublets centered at 3.58-2 methine hydrogens oncarbons attached to both phenyl and sec-butyl groups,

broad absorption between 0.5 and 2.16-18 aliphatic hydrogens of 2sec-butyl groups.

The following Examples 71 1 show the use of the alkyllithium adducts ascatalysts for anionic polymerizations in accordance with our presentinvention. All solvents, monomers and glassware were thoroughly driedbefore use in polymerization. Solvents and monomers were distilled andused immediately afterwards.

EXAMPLE 7 The deep red solution of the sec-butyllithium distyrylbenzeneadduct prepared in Example 6 above was used as a catalyst to initiatethe polymerization of 1,3- butadicne. 17.6 g of 1,3-butadiene and 120 mlof cyclohexane were added to a 250 ml polymerization bottle. 10 ml ofthe solution of Example 6 (0.0033 moles) was then added to the contentsof the bottle. Polymerization occurred slowly, the original red color ofthe solution gradually being replaced by the yellow color of thepolybutadienylanion. After 3 days, the polymerization was terminatedwith 1 ml of isopropanol. The product was dried by vacuum distillationto give 19 g of polybutadiene (100 percent conversion). NMR analysis ofthe polymer showed it to have a molecular weight of 8,250 (ratio ofolefinic to aromatic protons). The theoretical molecular weight forpolybutadiene catalyzed by a fully difunctional initiator is 10,700.

EXAMPLE 8 12.3 g of styrene and 100 ml of benzene were added to a 250 mlpolymerization bottle. 16.5 mmoles of the alkyllithium adduct of Example1 above was then added to the contents of the bottle. Initiation ofpolymerization occurred in less than 5 minutes as indicated by heatevolution and a color change from an orange-red to a bright cherry-red.The polymerization was allowed to proceed for 18 hours at roomtemperature. The difunctional polymer was terminated with 0.5 ml ofisopropanol and dried by vacuum distillation. 12.5 g of polystyrene wasobtained, indicating 100 percent conversion of monomer to polymer. Thenumber average molecular weight (M,,) of the polystyrene as determinedby vapor pressure osmometry was 14,500. The theoretical molecular weightcalculated for polystyrene prepared from a difunctional catalyst was14,800. Gel permeation chromatography of this polymer showed themolecular weight distribution to be very narrow (1.1 or less) and, thus,essentially monodisperse.

EXAMPLE 9 9.9 g of isoprene and 100 ml of benzene were added to a 250 mlpolymerization bottle. 16.5 mmoles of the alkyllithium adduct of Example1 above was added to the contents of the bottle. Initiation was rapid asindicated by a color change of the solution from orangered to lightyellow. Evolution of heat was noted after about 20 minutes. Thepolymerization was allowed to proceed for 18 hours at room temperature.The difunctional polymer was terminated with 0.5 ml of isopropanol and70 mg of antioxidant (N-phenyl-2-- naphthylamine) was added. The polymerwas dried by vacuum distillation. 10.5 g of polyisoprene was obtained,indicating a 100 percent conversion of monomer to polymer. The numberaverage molecular weight (171 as determined by vapor pressure osmometrywas 12,400. The theoretical molecular weight, calculated on the basis ofa difunctional initiator, was 12,400. Gel permeation chromatography ofthis polymer showed the molecular weight distribution to be very narrow(1.1 or less) and, thus, essentially monodisperse. The microstructure ofthe polymer, as determined by NMR and IR, was 78 percent trans-1,4 andcis-l ,4; and 22% vinyl.

EXAMPLE 10 13.75 g of 1,3-butadiene and 130 ml of benzene were added toa 250 ml polymerization bottle and 16.5 mmoles of the alkyllithiumadduct of Example 1 was added. Initiation was rapid as indicated by achange in the color of the solution from an orange-red to a lightyellow. Evolution of heat was noted within 20 minutes. Thepolymerization was allowed to proceed for 18 hours at room temperatureand was then terminated with 0.5 ml of propanol. After drying, thepolymer weighed 14.5 g indicating 100 percent conversion of monomer topolymer. The number average molecular weight, as determined byosmometry, was 14,000. The theoretical molecular weight, calculated forpolybutadiene obtained from a difunctional initiator, was 16,600. Gelpermeation chromatography of this polymer showed the molecular weightdistribution to be narrow, but containing some low molecular weighttailing. The microstructure of the polymer, as determined by NMR, was75.5 percent transand cis-l,4; and 24.5 percent vinyl.

EXAMPLE 1 l A rubbery triblock polymer (SIS) of isoprene (I) and styrene(S) was prepared using the alkyllithium adduct of Example 1. Into apolymerization vessel was placed 250 ml of benzene, 0.385 mmoles of thealkyllithium adduct of Example 1 and 21.0 g of isoprene. Afterpolymerization of isoprene was complete, 9.8 g of styrene was added andthe polymerization allowed to continue. The polymerization was finallyquenched in isopropanol, the precipitated polymer dried and antioxidantadded. The molecular weight (M,,) as determined by the formula, M,(grams monomer)/(0.5 [Initiator] was 160,000. The molecular weight (M,,)found by membrane osmometry was 170,000. Infra-red analysis of thethermo-plastic elastomer showed the microstructure of the polyisoprenecenter block to be approximately -70 percent cis-l ,4, 20-25 percenttrans-1,4 and 5-10 percent 3,4. Gel permeation chromatography of a 0.25percent solution of the polymer in tetrahydrofuran, using 5 consecutivecolumns of varying interstitial pore sizes, resulted in a symmetricalmolecular weight distribution curve, indicating the presence of anessentially monodisperse product. The tensile strength of a sample ofthe polymer cast as a clear film from THE solution was found to be 210kg/cm Commercial sources of the reactants can, of course, be utilized inthe practice of our invention. Thus, for-instance, in the case ofm-divinylbenzene, certain commercial sources thereof comprise about 80percent of a mixture of mand p-divinylbenzenes and about 20 percent ofm-ethylvinylbenzene and p-ethylvinylbenzene. When reacted with thealkyllithiums, the adducts are formed and then any remainingalkyllithium metalates the ethylvinylbenzenes. This, however, does notinterfere in any material way with the results which are obtained in theproperties of the initiator or in the properties of the polymers.

We claim:

1. A process for preparing a polymer of a conjugated diene and/orvinyl-substituted aromatic compound which comprises contacting at leastone polymerizable monomer of the group of conjugated dienes containingfrom four to 12 carbon atoms per molecule and vinylsubstituted aromaticcompounds in a solution of predominately liquid hydrocarbon medium withan initiator composition, said solution comprising (a) a liquid mediumof at least one member selected from the group consisting of aliphatic,cycloaliphatic and aromatic hydrocarbons, (b) at least one memberselected from the group consisting of aliphatic tertiary monoaminespossessing no methyl groups, arylalkyl tertiary monoamines and arylethers, and (c) an adduct of l to 100 moles of at least onepolymerizable monomer selected from the group of conjugated dienescontaining from four to 12 carbon atoms per molecule andvinyl-substituted aromatic compounds with 1 mole of a C C alkyllithium,said initiator composition being substantially free of polymers of saidconjugated dienes and/or of said vinyl-substituted aromatic compounds,said initiator composition being essentially free of unreactedalkyllithium, and recovering the resulting polymer.

2. A process according to claim 1 in which the polymer is al,3-butadien'e polymer possessing not substantially less than 75 percentof 1,4 links, and wherein the monomer is 1,3-butadiene.

3. A process according to claim 2 in which the adduct corresponds to theformula Li on;

4. A process according to claim 2 in which the adduct corresponds to theformula C112 Li 5. A process according to claim 2 in which the adductcorresponds to the formula i (1H3 ClIaCIIzCH I, oH-omoin ll 41 I Q'on-cu G cit-cir- O 6. A process according to claim 1 in which thepolymer is a styrene polymer, and wherein the monomer is styrene.

7. A process according to claim 6 in which the adduct corresponds to theformula CH: Li

2. A process according to claim 1 in which the polymer is a1,3-butadiene polymer possessing not substantially less than 75 percentof 1,4 links, and wherein the monomer is 1,3-butadiene.
 3. A processaccording to claim 2 in which the adduct corresponds to the formula
 4. Aprocess according to claim 2 in which the adduct corresponds to theformula
 5. A process according to claim 2 in which the adductcorresponds to the formula
 6. A process according to claim 1 in whichthe polymer is a styrene polymer, and wherein the monomer is styrene. 7.A process according to claim 6 in which the adduct corresponds to theformula
 8. A process according to claim 7 in which the polymer is acopolymer of styrene and 1,3-butadiene and wherein the solution iscontacted sequentially first with 1,3-butadiene and then with styreneunder polymerization conditions, and recovering the resultant copolymerthe central polybutadiene block of which possesses not substantiallyless than 75 percent of 1,4 links.